Source: Wikipedia
Negative free bid is a contract bridge treatment whereby a free bid by responder over an opponent’s overcall shows a long suit in a weak hand and is not forcing. This is in contrast with standard treatment, where a free bid can show unlimited values and is unconditionally forcing. The treatment is a relatively recent invention, and has become quite popular, especially in expert circles.
Negative free bids resolve relatively frequent situations where the responder holds a long suit with which he would like to compete for a partscore, but is deprived from bidding it by opponent’s overcall.
Example:
| West |
North |
East |
South |
|
1 |
1 |
? |
For example, if South holds:
86
KJ10852 K6 
532, partner opens 1
and East overcalls 1
, he couldn’t bid 2
in standard methods, as it would show 10+ high-card points, and a negative double would be too off-shape. With NFB treatment in effect though, he can bid 2
which the partner may pass (unless he has extra values and support, or an excellent suit of its own without tolerance for hearts).
However, as a corollary, negative free bids affect the scope of negative double; if the hand is suitable for “standard” forcing free bid (10-11+ points), a negative double has to be made first and the suit bid only in the next round. Thus, the negative double can be made with the following types of hand:
- A weakish hand with unbid suits (unbid major)
- A stronger hand with unbid suits
- A strong (opening bid or more) one-suited hand.
This can sometimes allow the opponents to preempt effectively.
| West |
North |
East |
South |
| 1 |
1 |
Dbl |
4 |
| ? |
|
|
|
For example, West, holding:
KJ103 J8 AKQ104 J2, after this auction is in an awkward situation — he doesn’t know whether partner has spades or not; whether South was bidding to make or to sacrifice — is it correct to double, bid 4
or pass?
